After years of planning what promises to be Silicon Valley's most iconic landmark, Apple this week enters the final stretch in its plan to open its new saucer-shaped headquarters in Cupertino. On Tuesday afternoon, the company and city officials will hold a public discussion that could help determine the building's fate, allowing political leaders and the public to weigh in on the completed environmental impact study and learn how Apple intends to address concerns that have been raised.

"The good news is that the EIR appears to have been very comprehensive, with every impact listed along with what Apple is doing to mitigate those impacts," Mayor Orrin Mahoney said Monday. "We've all received tons of emails about this project, and most have been positive. When I talk to neighbors and friends they say, 'How come they haven't started building it yet?'"

The building project, which Mahoney says is now rivaled only by One World Trade Center in New York City in terms of scope and size, is designed by world-famous architect Sir Norman Foster. With its four stories and 2.8 million square feet expected to house up to 14,200 employees, the architectural extravaganza is sure to draw tourists from around the world, planting Silicon Valley firmly on the map of ultracool corporate addresses.

If the plan is approved by the planning commission, which meets on Wednesday, and by the City Council, which takes an initial vote Oct. 15 and a final vote Nov. 19, city officials say demolition of a former Hewlett-Packard (HPQ) campus on the site could be underway by year's end.

While both the commission and council seem almost certain to give the project a green light, some supporters are taking no chances. Jim Reed with the Silicon Valley Chamber of Commerce said his group has asked its members to attend Tuesday's meeting to show support for Apple's ambitious plans.

"People need to speak up on behalf of this project," he said. "You'd think, Who wouldn't want a marquee building like this in their town? But you can't assume anything. So we'll be there to support Apple, because this project is important not just for Cupertino but for all of Silicon Valley and the region's overall economy."

Mahoney says much of Tuesday's workshop will be devoted to concerns the community has raised over the project's potential impact on traffic patterns, especially during the morning commute, when the neighborhood's roadways already are heavily congested. He says that while extra lanes are planned for the Wolfe Road exit in both directions, there is a limit to how much any developer can do to satisfy everyone.

"No matter how much some people might want it, Apple simply can't add another lane to Interstate 280," said the mayor. "It's physically impossible."

Mahoney said a detailed model of the headquarters will be unveiled to the public in the coming weeks, showing how expansive and impressive Foster's strange-looking creation really is. Amenities include three restaurants, totaling 120,000 square feet, along with a corporate auditorium of 120,000 square feet, fitness centers and a large testing-and-data center.

Some design details may be discussed at Tuesday's workshops, although officials say much of the meeting will deal with traffic, including a presentation by Apple's consultants, Fehr & Peers.

"I'm not sure how long the workshop will go on," city spokesman Rick Kitson said. "But since this is the biggest project in Cupertino's history, it could take some time."

Contact Patrick May at 408-920-5689 or follow him at Twitter.com/patmaymerc.